Gesture-based user-interface with user-feedback

ABSTRACT

A system has a contactless user-interface through which a user controls a functionality of the system. The contactless user-interface has a detector sub-system and a user-feedback sub-system. The contactless user-interface has an alert mode and a control mode. In the alert mode, the user-feedback sub-system has a display monitor to provide a visible acknowledgement to the user, in response to the detector sub-system having detected the presence of the user within a an alert range. The contactless user-interface transitions from the alert mode to the control mode in response to the detector sub-system detecting an initialization gesture of the user. In the control mode, the contactless user-interface controls the functionality in response to the detector subsystem detecting a control gesture of the user. The visible acknowledgement is made to mirror the movements of the user.

FIELD OF THE INVENTION

The invention relates to a system with a contactless user-interfaceconfigured for a user controlling a functionality of the system throughcontactless interaction with the contactless user-interface. Theinvention further relates to a user-interface for use in such a system,to control software on a computer-readable medium configured for use onsuch a system, and to a method of enabling a user to control afunctionality of such system through contactless interaction with thesystem.

BACKGROUND ART

User-interfaces are well in the field of man-machine interaction. Auser-interface of a system, e.g., an appliance, a mechanical system, acomputing system, an electronic system, etc., is designed to enable ahuman being to operate or control the system in operational use, or toconfigure the system for operational use. The term “system”, as usedthroughout this text, is meant to cover equipment for industrial orprofessional application, equipment for office or business application,medical equipment, equipment for domestic application, consumerelectronics equipment, etc.

A particular type of user-interface is a contactless user-interface,whose operation is based on the detection of a motion or movement of theuser who is not in haptic contact with the contactless user-interface.Examples of such a contactless user-interface, known in the art, are agesture-based user-interface and a motion-tracking user-interface.

A gesture-based user-interface interprets human gestures that originatefrom any bodily motion, typically from the face of the user or a hand ofthe user. See, e.g., US patent application publication 20030095154“Method and Apparatus for a Gesture-based User-interface”, US patentapplication publication 20070124694 “Gesture to Define Location, Size,and/or Content of Content Window on a Display”, US patent applicationpublication 20080253519 “Automatic Control of a Medical Device”, USpatent application publication 20100162177 “Interactive EntertainmentSystem and Method of Operation thereof”, all assigned to KoninklijkePhilips Electronics N.V., and incorporated herein by reference.

A motion-tracking user-interface tracks the movement of an object, e.g.,the user's head or a stylus held in the user's hand. The motion-trackinguser-interface translates the movement of the object to a movement of apointer displayed on the screen of a display monitor and interprets thepresence of the pointer within a specific zone of the screen as aspecific command. See, e.g., US patent application publication20090153474 “Motion Tracking User Interface”, Assigned to Apple, Inc.,and incorporated herein by reference.

Operation of a contactless user-interface, whose operation is based onthe detection of a motion or movement of the user, is typically based onpattern-recognition of the user-input captured by, e.g., one or morevideo cameras, one or more optical sensors, or one or more ultrasoundsensors.

Contactless user-interfaces do not require physical contact between theuser and a surface of the contactless user-interface. As a result, acontactless user-interface is less prone to wear, to being physicallydamaged, or to accumulating dirt at the surface, than areuser-interfaces that do require a physical contact between the user andthe surface. A contactless user-interface is also more hygienic from theoperator's point of view as physical contact is not required.

SUMMARY OF THE INVENTION

The inventors have recognized that typical, known, implementations ofthe contactless user-interface have several drawbacks. One drawbackrelates to the fact that user-interaction with the contactlessuser-interface may give rise to false positives, false negatives, andinput errors. A false positive occurs when an unintended movement of theuser is interpreted as a specific gesture to provide specific user-inputto the system. A false negative occurs when a deliberate movement of theuser fails to get interpreted as a specific gesture to provide specificuser-input to the system. An interpretation error occurs when adeliberate movement of the user is incorrectly interpreted and is mappedto the incorrect user-input to the system. Another drawback relates tothe fact that the user may be left in a state of uncertainty for a whileif the system does not seem to respond to the gesture. The user may evenwonder whether the power supply has failed, or whether the system hasbroken down, etc.

According to the inventors, studies show that users of a system withsuch a contactless user-interface typically seek confirmation of thecurrent status of the system to understand what has gone wrong, if thesystem gives a false positive response, a false negative response, anincorrect response or no response at all.

Known systems, whose user-input is based on gesture recognition,typically present a representation of what the user-interface isactually sensing or capturing on a screen of a display monitor that atthe same time is also being used to track the system's current operationor status. Accordingly, the display monitor is being used in dual-modeoperation: presenting the current operation of the system in a firstwindow as well as presenting the user-input being sensed or captured ina second window. Such a dual-mode configuration has a number ofdisadvantages. A first disadvantage is that the dual-mode configurationneeds screen real-estate. That is, the dual-mode configuration imposesconstraints on the minimum size of the screen so as to be large enoughin order to provide meaningful visual feedback to the user in each ofthe first window and second window. A second disadvantage relates to theergonomic aspect of the dual-mode configuration, as the user has to payattention to two sources of information at the same time: the firstwindow and the second window being present on the same screen of thedisplay monitor at the same time. This is believed to be confusing, asthe user has repeatedly to switch mentally between controlling thecurrent operation of the system and verifying the current user-input tothe system. A professional may be trained to do this intuitively wheninteracting with professional equipment such as a fighter plane, butthis approach is less attractive to users of everyday consumer products.

The inventors propose a system with a gesture-based, contactlessuser-interface wherein the contactless user-interface visualizes thedialogue between the user and the system in a more ergonomic way. Morespecifically, the inventors propose a system with a contactlessuser-interface. The contactless user-interface is configured for auser's controlling a functionality of the system through contactlessinteraction with the contactless user-interface. The contactlessuser-interface has a detector sub-system and a user-feedback sub-system.The contactless user-interface is configured for operating in an alertmode or in a control mode. In the alert mode, the contactlessuser-interface is configured for controlling the user-feedbacksub-system to provide an acknowledgement to the user, in response to thedetector sub-system having detected a presence of the user within apre-determined alert range. The contactless user-interface is configuredfor transitioning from the alert mode to the control mode in response tothe detector sub-system detecting a pre-determined initializationgesture made by the user within the pre-determined alert range. In thecontrol mode, the contactless user-interface is configured forcontrolling the functionality in response to the detector subsystemdetecting a pre-determined control gesture of the user carried outwithin the pre-determined alert range.

The system in the invention may be implemented as a geographicallyconcentrated entity such as an apparatus or a device. Alternatively, thesystem in the invention is a geographically distributed system, withentities that are spatially dispersed and that communicate via a datanetwork, such as, e.g., a local area network (LAN) or the Internet.

The term “functionality” as used in this text, refers to one or moreattributes characterizing the functioning of the system in operationaluse. The one or more attributes are controllable through thepre-determined control gesture. For example, the system comprises anaudio function with one or more of the following attributes: anintensity (volume) of the sound being reproduced, a directionalcharacter of the sound being reproduced in a stereo implementation ofthe audio function, the level of treble or of bass in the sound beingreproduced, an item of audio being played out and having been selectedfrom a playlist of multiple of such items, a radio channel currentlytuned into, etc. As another example, the system comprises a videofunction with one or more of the following attributes: a brightness ofthe images being played out on a display monitor, contrast in the imagesbeing played out on the display monitor, color adjustment of the imagesbeing played out, a resolution of the images being played out in a partof the screen of the display monitor, an item of video being played outand having been selected from a playlist of such video items, an imagebeing displayed and having been selected from a collection of pre-storedimages, a TV channel currently tuned into, etc. As another example, thesystem comprises a lamp such as a wake-up light, or a lamp to illuminatea dinner table, or a searchlight mounted on a vehicle of an emergenceservice, etc. The lamp has one or more of the following attributes: anon-state and an off-state; a brightness of the light emitted, adirection of the light emitted, a color temperature of the lightemitted, a focus of the light emitted, etc. As yet another example, thesystem comprises a domestic appliance such as a kitchen stove or amicrowave oven. The operation of the domestic appliance has one or moreof the following attributes: an intensity of the heat generated, apre-set length of the time-period during which heat is generated, aspecific one of multiple burners or of multiple coils selected toproduce the heat, etc. Above examples merely illustrate the field ofapplication of contactless user-interfaces and should not be interpretedas an exhaustive list of applications, neither with regard to the typeof system, nor with regard to the attributes controllable through thecontactless user-interface.

When the contactless user-interface is operating in the alert mode, theuser-feedback sub-system provides an acknowledgement to the user, inresponse to the detector sub-system having detected the presence of theuser within a pre-determined alert range. That is, when the user, orpart of his/her body, has come within the alert range of the detectorsub-system, the user-feedback sub-system acknowledges to the user thathis/her presence has been detected. The acknowledgement serves as afeedback to the user and makes the user aware of the fact that thedetector sub-system has noticed the user and that he/she is now withinthe alert range. When the user, or a bodily part of the user, is withinthe alert range, the contactless user-interface responds to thepre-determined initialization gesture of the user and transitions to thecontrol mode. In the control mode, the user is given control over thefunctionality of the system via user-interaction with the contactlessuser-interface. In the control mode, the contactless user-interfaceresponds to the pre-determined control gesture by controlling thefunctionality of the system in accordance with the pre-determinedcontrol gesture.

As specified above, operation of the contactless user-interfacetransitions from the alert mode to the control mode in response to thedetector sub-system detecting the pre-determined initialization gesture.The pre-determined initialization gesture comprises, for example, theuser keeping his/her hand steady for a pre-determined length of time,e.g., a few seconds, relative to the contactless user-interface. Asanother example, the pre-determined initialization gesture comprises theuser waving his/her hand in front of the contactless user-interface at afrequency that is higher than a pre-determined threshold. As yet anotherexample, the pre-determined initialization gesture is a movement of theuser's hand along a path (or: a trajectory) in three-dimensional space,the path having one or more pre-determined spatial characteristics.

A gesture is a deliberate movement of a position of the user's hand, orarm, or head, or body. An actual movement of, e.g., the user's handincludes a change of position of the hand relative to some referenceposition, a change of orientation of the hand relative to a referenceorientation, and a change of the shape of the hand relative to areference shape. In practice, therefore, an actual movement cannot berepeated exactly with an accuracy of, say a few millimeters in each ofthe dimensions characterizing the movement. The expression“pre-determined initialization gesture”, as used in this text, referstherefore to a specific class of multiple gestures that are allinterpreted by the detector sub-system as representative of thepre-determined initialization gesture. For example, consider the centerof gravity of the user's hand and consider a gesture as characterized bythe directed path traversed by the center of gravity of the user's handin a three-dimensional space. The detector sub-system may then beconfigured to determine the main spatial vector component of thedirected path. The directed path can be represented by athree-dimensional vector that connects the starting position of the pathwith the current position of the path. While the user is carrying outthe gesture, the three-dimensional vector changes. The main spatialvector component is then the specific one of the three vectorcomponents, which has the largest magnitude. If the magnitude of themain spatial component lies within a pre-determined range of magnitudes,the gesture is interpreted as being the pre-determined initializationgesture. Alternative procedures may be implemented in order to determinewhether an actual gesture as detected should be interpreted as thepre-determined initialization gesture. Similar considerations apply tothe feature “pre-determined control gesture. Gesture-baseduser-interfaces are well known in the art and are operative todiscriminate between different user inputs in the form of differentgestures. The discriminating between gestures is known in the art andis, therefore, not addressed in further detail in this text.

In an embodiment of the system, the user-feedback sub-system isconfigured to provide to the user control feedback on a change in astatus of the functionality in response to the pre-determined controlgesture.

Accordingly, the user will receive the acknowledgment as a feedback inthe alert mode of the contactless user-interface in order to inform theuser that he/she has been detected. Gesture control is disabled in thealert mode. Upon the pre-determined initialization gesture, thecontactless user-interface transitions to the control mode whereingesture control is enabled. In the control mode, the user receivescontrol feedback on the status change of the functionality brought aboutby the pre-determined control gestures. The control feedback comprises,for example, a graphics object representing a slider, a dial, a lever oranother familiar physical control device, or a menu of selectableoptions. The graphics representation is displayed on a display monitorand is changed synchronously with the pre-determined control gesturebeing carried out by the user. The changing of the graphics object thusmirrors the temporal characteristics of the pre-determined controlgesture being carried out. That is, the user-feedback sub-system isconfigured for dynamically adjusting the control feedback under controlof the detector sub-system tracking the user within the alert range. Theuser-feedback sub-system thus provides feedback to the user in order toconfirm, e.g., visually or audibly, the tracking of the user'spre-determined control gesture. At the same time, the functionality ofthe system is controlled synchronically with the pre-determined controlgesture. The feedback mirrors the user's pre-determined control gesture,thus strengthening the user's impression that the system is in contactwith the user.

In an embodiment of the system, the user-feedback sub-system isconfigured for dynamically adjusting the acknowledgement under controlof the detector sub-system tracking the user within the alert range.

As specified above, when the contactless user-interface is operating inthe alert mode, the user-feedback sub-system provides an acknowledgementto the user, in response to the detector sub-system having detected thepresence of the user within a pre-determined alert range. That is, whenthe user, or part of his/her body, has come within the alert range ofthe detector sub-system, the user-feedback sub-system acknowledges tothe user that his/her presence has been detected.

The acknowledgement feedback to the user may be implemented in a varietyof ways. For example, the user-feedback system comprises a small light,e.g., a colored LED, that starts to blink or that lights up when thedetector sub-system has detected the user's presence within the alertrange. As another example, the user-feedback system comprises an arrayof small lamps, e.g., an arrangement of multiple LEDs that arerepeatedly turned on and off selectively so as to create a ripplingeffect.

The acknowledgement in the form of repeatedly turning on and off of theLEDs may be made dynamically adjustable in dependence on the movementsof the user. The detector sub-system is then tracking the user withinthe alert range and adjusts the behavior of the LEDs to reflect theuser's movements as detected. The rippling effect, mentioned above, maythen have a directional characteristic reflecting the main component ofa direction from which the user has been detected to move into and/orwithin the alert range. The arrangement of the multiple LEDs iscontrolled so as to have the LEDs are turned on or off in synchronismwith the movements of the user so as to mirror the movements of theuser.

As another example, the user-feedback system comprises a displaymonitor. The display monitor serves to provide visual information to theuser about, e.g., the functioning of the system in operational use. Ifthe system comprises a domestic central heating system or aclimate-control system, the display monitor is used to convey to theuser information in a graphics format about, e.g., the current ambienttemperature, the current relative humidity of the ambient air, whetherthe heating system or the climate-control system idles or is consumingpower. If the system comprises a clock, the display monitor is used, inoperational use of the system, to convey to the user the current time ofthe day by means of, e.g., a graphics representation of an analog clockhaving a clock face and moving hands, or a graphics representation of adigital clock with numerical representations of the hours and theminutes. Accordingly, the display monitor conveys information with asemantic content to the user in operational use of the system. When thedetector sub-system detects the presence of the user, the contactlessuser-interface controls the system so that the information, beingdisplayed on the display monitor in operational use of the system, isreplaced by a dedicated indication to acknowledge to the user thathis/her presence has been detected. The replacing may be done in avariety of manners. For example, the information displayed inoperational use of the system fades out while the dedicated indicationfades in. As another example, the information being displayed inoperational use of the system is morphed into the indication. Theoperation of cross-fading or of morphing shifts the attention of theuser smoothly, i.e., non-abruptly, from one state of the contactlessuser-interface to a next state. This smooth shifting of the attentioncauses the user to accept by intuition the new state as arisingnaturally from the preceding state. Thus, the cross-fading or morphingcontributes to improving the ergonomic, user-friendliness related,aspects of the contactless user-interface in the invention.

The information being displayed on the display monitor in operationaluse of the system is then faded or morphed into a collection of graphicsparticles that move in synchronism with the movements of the user. Themirroring of the movements of the user serves to strengthen theimpression of the user that he/she has been detected within the alertrange.

The mirroring may have a further psychological effect on the user ofwhich he/she will generally not be aware. The term “mirroring”, as usedin the field of psychology, refers to social interaction betweenindividuals, in which an individual copies the gestures, body language,facial expressions, or natural language of another individual. Mirroringis typically observed among couples and among close friends. Usually,people readily accept their mirror images and, as a result, mirroringthe person with whom one is speaking generally makes the person feelmore relaxed and at ease with the other. If an apparatus or a system ismirroring the movements of the user, the user is more likely to feelsympathetic towards the apparatus or system. Accordingly, the mirroringof the user's movements by a graphic's object on the display monitortends to make the user perceive the system as user-friendly, and tendsto make the user feel more emphatic towards the system. The mirroringfeature of the contactless user-interface in the alert mode as well asin the control mode can therefore be considered an ergonomic featurethat readily speeds-up user-acceptance of the system.

Accordingly, when the contactless user-interface in the invention is inthe alert mode, the contactless user-interface responds to the detectorsub-system detecting the user or, e.g., the user's hand or leg, withinthe pre-determined alert range. The contactless user-interface controlsthe display monitor in the user-feedback sub-system to display anacknowledgment to the user of his/her presence having been noticed. Theacknowledgement may be abstract or figurative. For example, assume thatthe display monitor had been blank or switched off before the user'spresence was detected. Upon detection of the user within thepre-determined range, the display monitor is started to display theacknowledgment as a graphics object, e.g., a graphics representation ofa human hand, or a graphics representation of an amorphous collection ofparticles, or the letters of the word “hello”, etc. The user-feedbacksub-system then controls the graphics object to moves in unison with theuser. As another example, assume that the display monitor had beendisplaying an indicator before the user's presence got detected. Forexample, the indicator includes a graphics representation of atime-piece to indicate the current time of the day, or a graphicsrepresentation of a thermometer indicating the current ambienttemperature, or a graphics representation of a piece of audio beingcurrently rendered, etc. Upon detection of the user within thepre-determined range, the user-feedback sub-system controls the displaymonitor to morph the graphics representation of the indicator into theacknowledgment in the form of a graphics representation of anotherobject, e.g., the graphics representations of a human hand, or of anamorphous collection of particles, or of the word “hello”, etc. Thecontactless user-interface then controls this other graphics object tomove in a continuous way and synchronized with the user.

In a further embodiment of a system of the invention, the system has anadditional user-interface. The additional user-interface is configuredfor the user's controlling an additional functionality of the systemthrough physical contact with the additional user-interface. Thedetector sub-system is operative to inactivate the user controlling thefunctionality via the contactless user-interface upon detecting the userapproaching the additional user-interface in a pre-determined manner.

In this further embodiment, the system is configured for beingcontrolled by the user via the contactless user-interface as well as viathe additional user-interface. The additional user-interface requiresthat the user physically contact the additional user-interface. Theadditional user-interface comprises, e.g., one or more buttons, and/orone or more dials, and/or one or more sliders, and/or one or morelevers, and/or a touch screen. The first-mentioned functionality of thesystem is user-controllable via the contactless user-interface, and theadditional functionality of the system is user-controllable via theadditional user-interface. The first-mentioned functionality may bedifferent from the additional functionality. Alternatively, thefirst-mentioned functionality may be the same as the additionalfunctionality.

If the user has not carried out the pre-determined initializationgesture within the alert range prior to approaching the additionaluser-interface, the gestures or other movements of the user within thepre-determined alert range will not result in unintended control of thefunctionality, as the contactless user-interface has not transitioned tothe control mode. If the user caused the contactless user-interface totransition to the control mode prior to approaching the additionaluser-interface, the contactless user-interface would be tracking themovements and gestures of the user within the pre-determined alertrange. As a result, the contactless user-interface could then interpretthe movements of the user, reaching for the additional user-interface,as the pre-determined control gesture and start controlling thefunctionality, contrary to the intention of the user. Accordingly, ifthe detector sub-system detects the user reaching for the controloptions of the additional user-interface while the contactlessuser-interface is in the control mode, the detector sub-systeminactivates the control mode in order to prevent unintended control ofthe functionality via the contactless user-interface.

The detector sub-system may be configured in a variety of manners todetect the user reaching for the control options in the additionaluser-interface. For example, consider a movement or a gesture of theuser as a directed path within the pre-determined alert range, asmentioned earlier. If the main vector component of the vector,representing the directed path, lies in the direction from the usertowards the additional user-interface, and if the rate of change of thismain vector component exceeds a pre-determined threshold magnitude at acertain moment, the detector sub-system interprets the movement orgesture as that the user is reaching for the additional user-interface.

Assume that the contactless user-interface has already started tocontrol the functionality in response to the movement of the userreaching for the control options in the additional user-interface.Preferably, the contactless user-interface is configured for resettingthe functionality to the state the functionality had before starting tocontrol the functionality, upon the user actually touching, or actuallyinteracting with, the additional user-interface.

Consider the system having one or more functionalities that can becontrolled by the user via the contactless user-interface. The directedpath of any respective one of the pre-determined control gestures doespreferably not have a vector component in the direction from the usertowards the additional user-interface. If the directed path of aparticular one of the pre-determined control gestures does have a mainvector component along this direction, the contactless user-interface ispreferably configured in such as way that the functionality, associatedwith this particular pre-determined control gesture, is not a criticalfunctionality. The expression “critical functionality”, as used herein,refers to a functionality whose unintended control does not lead todamaging the system or to scaring or agitating the user. For example,consider a functionality that includes the adjusting of the volume ofthe sounds being played out by the system. It is then preferred that thedirected path of the pre-determined “volume-up”-gesture lacks a vectorcomponent in the direction from the user to the additional controls.

The invention as described above relates to a system as an entity thatcan be commercially exploited. The invention may also be commerciallyexploited as control software to be run on a data processing system suchas, e.g., a server, a personal computer, a mobile telephone, etc. Thecontrol software may be provided as stored in a computer-readable mediumsuch as a solid-state memory, a magnetic disc, an optical disk, etc. Thecontrol software may also be made commercially available as a filedownload via a data network such as the Internet.

Therefore, the invention also relates to control software on acomputer-readable medium configured for use on a system with acontactless user-interface. The contactless user-interface is configuredfor a user's controlling a functionality of the system throughcontactless interaction with the contactless user-interface. Thecontactless user-interface has a detector sub-system and a user-feedbacksub-system. The control software has first instructions for implementingoperation of the contactless user-interface in an alert mode, and secondinstructions for implementing operation of the contactlessuser-interface in a control mode. The first instructions comprise thirdinstructions for controlling the user-feedback sub-system to provide anacknowledgement to the user, in response to the detector sub-systemhaving detected a presence of the user within a pre-determined alertrange. The first instructions comprise fourth instructions for causingthe contactless user-interface to transition from the alert mode to thecontrol mode in response to the detector sub-system detecting apre-determined initialization gesture made by the user within thepre-determined alert range. The second instructions comprise fifthinstructions for controlling the functionality in response to thedetector subsystem detecting a pre-determined control gesture of theuser carried out within the pre-determined alert range.

In an embodiment of the control software, the second instructionscomprise sixth instructions for controlling the user-feedback sub-systemto provide to the user control feedback on a change in a status of thefunctionality in response to the pre-determined control gesture.

In a further embodiment of the control software, the first instructionscomprise seventh instructions for control of the user-feedbacksub-system for dynamically adjusting the acknowledgement under controlof the detector sub-system tracking the user within the alert range.

In a further embodiment of the control software, the second instructionscomprise ninth instructions for controlling the user-feedback sub-systemto dynamically adjust the control feedback under control of the detectorsub-system tracking the user within the alert range.

In a further embodiment of the control software, the system has anadditional user-interface. The additional user-interface is configuredfor the user's controlling an additional functionality of the systemthrough physical contact with the additional user-interface. The secondinstructions comprise tenth instructions for inactivating the usercontrolling the functionality via the contactless user-interface uponthe detector sub-system detecting the user approaching the additionaluser-interface in a pre-determined manner.

The invention may also be commercially exploited as a service or method.The invention therefore also relates to a method of enabling a user tocontrol a functionality of a system through contactless interaction withthe system. The method has an alert mode process and a control modeprocess. The method comprises, in the alert mode process, providing anacknowledgement to the user, in response to detecting a presence of theuser within a pre-determined alert range. The method further comprises:transitioning from the alert mode process to the control mode process inresponse to detecting a pre-determined initialization gesture made bythe user within the pre-determined alert range. The method alsocomprises: in the control mode process, controlling the functionality inresponse to detecting a pre-determined control gesture of the usercarried out within the pre-determined alert range.

In an embodiment of the method, the control mode process comprisesproviding to the user control feedback on a change in a status of thefunctionality in response to the pre-determined control gesture.

In a further embodiment of the method, the alert mode process comprisesdynamically adjusting the acknowledgement under control of tracking theuser within the alert range.

In a further embodiment of the method, the control mode processcomprises dynamically adjusting the control feedback under control oftracking the user within the alert range.

In a further embodiment of the method, the system has an additionaluser-interface. The additional user-interface is configured for theuser's controlling an additional functionality of the system throughphysical contact with the additional user-interface. The methodcomprises inactivating the controlling of the functionality through thecontactless interaction upon detecting the user approaching theadditional user-interface in a pre-determined manner.

The invention may also be commercially exploited as a component for asystem with a controllable functionality. The invention therefore alsorelates to a user-interface for use in a system, the user-interfacecomprising a contactless user-interface configured for a user'scontrolling a functionality of the system through contactlessinteraction with the contactless user-interface. The contactlessuser-interface has a detector sub-system and a user-feedback sub-system.The contactless user-interface is configured for operating in one of: analert mode and a control mode. In the alert mode, the contactlessuser-interface is configured for controlling the user-feedbacksub-system to provide an acknowledgement to the user, in response to thedetector sub-system having detected a presence of the user within apre-determined alert range. The contactless user-interface is configuredfor transitioning from the alert mode to the control mode in response tothe detector sub-system detecting a pre-determined initializationgesture made by the user within the pre-determined alert range. In thecontrol mode, the contactless user-interface is configured forcontrolling the functionality in response to the detector subsystemdetecting a pre-determined control gesture of the user carried outwithin the pre-determined alert range.

In an embodiment of the user-interface, the user-feedback sub-system isconfigured to provide to the user control feedback on a change in astatus of the functionality in response to the pre-determined controlgesture.

In a further embodiment of the user-interface, the user-feedbacksub-system is configured for dynamically adjusting the acknowledgementunder control of the detector sub-system tracking the user within thealert range.

In a further embodiment of the user-interface, the user-feedbacksub-system is configured for dynamically adjusting the control feedbackunder control of the detector sub-system tracking the user within thealert range.

In a further embodiment of the user-interface, the user-interface has anadditional user-interface. The additional user-interface is configuredfor the user's controlling an additional functionality of the systemthrough physical contact with the additional user-interface. Thedetector sub-system is operative to inactivate the user controlling thefunctionality via the contactless user-interface upon detecting the userapproaching the additional user-interface in a pre-determined manner.

BRIEF DESCRIPTION OF THE DRAWING

The invention is explained in further detail, by way of example and withreference to the accompanying drawing, wherein:

FIG. 1 is a block diagram of a system in the invention;

FIGS. 2, 3 and 4 are diagrams illustrating operation of the detectorsub-system in the system of the invention;

FIG. 5 is a process diagram illustrating a method of the invention;

FIGS. 6, 7, 8 and 9 illustrate a graphics representation of theacknowledgement from the user-feedback sub-system; and

FIGS. 10 and 11 illustrate a graphics representation of the controlfeedback from the user-feedback sub-system.

Throughout the Figures, similar or corresponding features are indicatedby same reference numerals.

DETAILED EMBODIMENTS

FIG. 1 is a diagram of a system 100 in the invention. Examples of such asystem 100 are: a consumer electronics system such as a homeentertainment system, an alarm clock, a TV receiver, a personalcomputer, etc.; a handheld device such as a mobile telephone or a remotecontrol device; an appliance, such as a microwave oven, a kitchen stoveor a laundry machine, etc. a vending machine for beverages, candy orother food items; a ticket machine; etc.

The system 100 has a functionality that can be controlled by a user toadjust the functionality, select the functionality for activating ordeactivating, etc. Examples of such functionality have been discussedabove.

The system 100 has a contactless user-interface 102 and a controlsub-system 104.

The contactless user-interface 102 enables the user of the system 100 tointeract with the system 100 in order to configure the system 100 foroperational use by means of, e.g., adjusting or selecting thefunctionality of the system 100. The user interacts with the contactlessuser-interface 102 through gestures. The gestures of the user arecaptured by the contactless user-interface 102 and form the user inputto the system 100. The contactless user-interface 102 processes theinput to generate a control output that is supplied to the controlsub-system 104. The control sub-system 104 receives the control outputfrom the contactless user-interface 102 and controls the functionalityaccordingly.

The contactless user-interface 102 comprises a detector sub-system 106,a data processing sub-system 108, and a user-feedback sub-system 110.

The detector sub-system 106 is configured for detecting of a presence ofthe user, or a body part of the user such as his/her hand or his/herhead, within an alert range of the detector. The detector sub-system 106is also configured for tracking the user or his/her hand or head, etc.,when present within the alert range of the detector.

Detection of the proximity of the user may be implemented by using anyof a variety of techniques to detect the proximity of the user or ofanother object within the alert range, or by using a combination ofthese techniques. For example, a first known proximity detectiontechnology is based on sensing body heat received via an infraredsensor. As another example, a second known proximity detectiontechnology is based on the detector transmitting pulses of ultrasonicwaves and measuring the reflection off the user or off another objectwithin the alert range. As yet another example, a third known proximitydetection technology is based on the user or the object interrupting oneor more light beams or laser beams. As still another example, a fourthproximity detection technology is based on sensing a change incapacitance caused by the capacitive coupling between the detector andthe nearby user or the nearby object. As yet another example, a fifthproximity detection technology is based on analysis of images capturedby a video camera that surveys a pre-determined space.

Detection of the movements of the user, or of a body part of the user,within the alert range may be implemented by using any of a variety oftechniques to detect the movements of the user or of another objectwithin the alert range, or a combination of these motion detectiontechniques. The movement may be a change of position of the user, or ofthe object as a whole, relative to the detector sub-system 106, and/orchange of orientation of the user or of the object relative to thedetector sub-system. Motion detection is based, for example, onanalyzing the rate of change of the proximity as detected with any ofaforesaid proximity detection techniques. The rate of change of theproximity as detected may indicate a movement away from, or towards thedetector sub-system 106, and/or a movement from left to right relativeto the detector sub-system 106 or vice versa, and/or an upwards ordownward movement relative to the detector sub-system 106, etc.

Proximity detectors and motion detectors are well known in the art.Therefore, the implementing technologies to make or use such detectorswill not be discussed here in further detail.

The detector sub-system 106 generates a detector output that isrepresentative of the user's movements as captured within thealert-range. The detector sub-system 106 supplies the detector output tothe data processing sub-system 108. The data processing sub-system 108processes the detector output as received and supplies a feedback outputto the user-feedback sub-system 110 and supplies the control output tothe control sub-system 104, as mentioned above.

The user-feedback sub-system 110 receives the feedback output from thedata processing sub-system 108. The feedback output received isrepresentative of the of the user's movements as captured by thedetector sub-system 106. The user-feedback sub-system 110 serves toprovide feedback to the user indicative of the feedback output and,therefore, of the user-interaction with the contactless user-interface102 as captured by the detector sub-system 106. The feedback to the usertypically comprises a visual feedback and/or an audible feedback.

The control sub-system 104 receives the control output from thecontactless user-interface 102. The control output is indicative of theuser-interaction with the contactless user-interface 102. The controlsub-system 104 controls the functionality in accordance with the controloutput received.

The contactless user-interface 102 has an alert mode and a control mode.In the alert mode, the user-feedback sub-system provides anacknowledgement to the user if the detector sub-system 106 has detectedthe presence of the user within the pre-determined alert range. In thealert mode, the gestures of the user, as captured by the detectorsub-system 106, do not result in the control-sub-system 104 receiving acontrol output. Accordingly, the functionality of the system 100 cannotbe controlled by the user making gestures within the alert range.

If the detector sub-system 106 detects a pre-determined initializinggesture of the user carried out within the alert range and while thecontactless user-interface 102 is in the alert mode, the contactlessuser-interface 102 transitions from the alert mode to the control mode.In the control mode, the contactless user-interface 102 controls thefunctionality via the control sub-system 104, in response to thedetector subsystem 106 detecting a pre-determined control gesture of theuser carried out within the pre-determined alert range.

The system 100 also has an additional user-interface 112. The additionaluser-interface 112 enables the user to control an additionalfunctionality of the system 100 through physical contact with theadditional user-interface 112. For example, the additionaluser-interface 112 has one or more physical buttons, physical sliders,or dials, or the additional user-interface 112 comprises a touch screen.The additional functionality and the functionality first-mentioned may,but need not, be the same functionality. The detector sub-system 106inactivates or overrides the control mode of the contactlessuser-interface 102 upon detecting that the user approaches theadditional user-interface 112 in a pre-determined manner. As explainedearlier, overriding the control mode in these circumstances prevents thefunctionality from being controlled inadvertently, in response to thecontactless user-interface 102 interpreting the user's reaching at theadditional user-interface 112 as a pre-determined control gesture.

FIGS. 2, 3 and 4 are diagrams illustrating operation of the detectorsub-system 106 in the system 100.

The diagram of FIG. 2 shows a first embodiment of the detectorsub-system 106 that is positioned in an environment of the user and thatfaces the user. The first embodiment of the detector sub-system 106responds to the movements of the user only if the user enters, or ispresent within, a part 202 of the environment. This part has beenreferred to in this text as the “alert range”. The contactlessuser-interface 102 provides an acknowledgement to the user when he/sheis present, entirely or only partly, within the alert range 202, so asto notify the user of his/her being noticed. If the user then carriesout the pre-determined initialization gesture within the alert range202, the contactless user-interface 102 transitions from the alert modeto the control mode. In the control mode, the contactless user-interface102 responds to pre-determined control gestures of the user, if carriedout within the alert range, by means of adjusting or otherwisecontrolling the functionality of the system 100. The alert range 202 isonly drawn schematically. The actual spatial shape and the dimensions ofthe alert range 202 depend on, among other things, the techniques usesto implement the detector sub-system 106. The diagram of FIG. 2illustrates the alert range 202 as being centered on an axis 204projecting from the detector sub-system 106, roughly in the direction ofthe user when facing the detector sub-system 106 in operational use.

The diagram of FIG. 2 shows a second embodiment of the detectorsub-system 106. In the second embodiment, the alert range 202 has a farcontrol sector 302 and a near control sector 304. The adjectives “far”and “near” qualify the distance as measured from the detector sub-system106. The near control sector 304 lies between the far control sector 302and the detector sub-system 106. Assume that the contactlessuser-interface 102 is in the control mode. If the user makes a firstpre-determined control gesture within the far control sector 302, thecontactless user-interface 102 responds by controlling a firstfunctionality of the system 100 in accordance with the firstpre-determined control gesture as captured by the detector sub-system106. If the user makes a second pre-determined control gesture,different from the first pre-determined control gesture, within the farcontrol sector 302, the contactless user-interface 102 does not respond.If the user makes the second pre-determined control gesture within thenear control sector 304, the contactless user-interface 102 responds bycontrolling a second functionality of the system 100 in accordance withthe second pre-determined control gesture as captured by the detectorsub-system 106.

More generally, the contactless user-interface 102 is configured torespond differently to different pre-determined control gestures carriedout within different control sectors, e.g., the first control sector 302and the second control sector 304, within the alert range 202.Alternatively, the contactless user-interface 102 is configured torespond differently to the same pre-determined control gesture carriedout in different control sectors within the alert range 202. The diagramof FIG. 4 illustrates this more general configuration.

In the diagram of FIG. 4, the alert range 202 (not shown separatelyhere) comprises a plurality of control sectors between the user and thedetector sub-system 106. The plurality of the control sectors have aspatial arrangement explained as follows with reference to a Cartesiancoordinate system 402. The Cartesian coordinate system 402 has anX-axis, a Y-axis and a Z-axis. The detector sub-system 106 faces adirection parallel to the positive X-axis.

If the user approaches the detector sub-system 106 along the X-axis, theuser first enters a first control sector 404. A projection of the firstcontrol sector 402 along the X-axis onto the detector sub-system 106overlaps the detector sub-system 106 completely. That is, the detectorsub-system 106 does not discriminate between a first pre-determinedcontrol gesture carried out in the upper half of the first controlsector 404 (Z is positive), the same first pre-determined controlgesture carried out in the lower half of the first control sector 404 (Zis negative), the same first pre-determined control gesture carried outin the left half of the first control sector 404 (Y is negative) and thesame first pre-determined control gesture carried out in the right halfof the first control sector 404 (Y is positive).

If the user continues to approach the detector sub-system 106 along theX-axis, the user exits the first control sector 404 and enters either asecond control sector 406 (Y is negative) or a third control sector 408(Y is positive). A projection of the second control sector 406 along theX-axis onto the detector sub-system 106 only overlaps a left-hand sideof the detector sub-system 106. A projection of the third control sector408 along the X-axis onto the detector sub-system 106 only overlaps aright-hand side of the detector sub-system 106. That is, apre-determined control gesture carried out in the second control sector406 leads to a response of the contactless user-interface 102 that isdifferent from the response to the same pre-determined control gesturewhen carried out in the third control sector 408, and vice versa.

If the user continues to approach the detector sub-system 106 along theX-axis, the user exits either the second control sector 406 or the thirdcontrol sector 408.

If the user exits the second control sector 406, the user enters eithera fourth control sector 410 or a fifth control sector 412. The fourthcontrol sector 410 is characterized by Z being positive and Y beingnegative. The fifth control sector 412 is characterized by Z beingnegative and Y being negative.

If the user exits the third control sector 408, the user enters either asixth control sector 414 or a seventh control sector 416. The sixthcontrol sector 414 is characterized by Z being positive and Y beingpositive. The seventh control sector 416 is characterized by Z beingnegative and Y being positive.

Accordingly, a pre-determined control gesture carried out in a specificone of the fourth control sector 410, the fifth control sector 412, thesixth control sector 414 and the seventh 416 leads to a response of thecontactless user-interface 102 that is different from the response tothe same pre-determined control gesture when carried out in another oneof the fourth control sector 410, the fifth control sector 412, thesixth control sector 414 and the seventh 416.

The closer the user gets to the detector sub-system 106, the moreaccurate will be the capturing of the path of the pre-determined controlgestures by the detector sub-system 106 and the better will be thediscriminating between two or more different pathos of thepre-determined control gestures. Therefore, the control sectors closerto the detector sub-system 106 can be made smaller than the controlsectors farther away from the detector sub-system 106.

FIG. 5 is a diagram of a process 500 illustrating a method of theinvention. It is assumed here that the user-feedback sub-system 110 hasa display monitor (not shown in FIG. 1). The user-feedback sub-system110 provides the acknowledgment in a graphics format via the displaymonitor upon the user entering the alert range 202. The user-feedbacksub-system 110 also provides to the user control feedback on a change ina status of the functionality in response to the pre-determined controlgesture.

In a first step 502, the power of the system 100 is turned on. Thecontactless user-interface 102 is then ready for operational use.

In a second step 504, the detector sub-system 106 checks whether theuser is within the alert range 202. If the user is not within the alertrange 202, the detector sub-system 106 continues to check whether theuser has entered the alert range 202. If the user has entered the alertrange 202, the process continues with a third step 506.

In the third step 506, the user-feedback sub-system 110 controls thedisplay monitor to show an acknowledgement in the form of a graphicsobject so as to notify the user that he/she has been detected within thealert range 202. The detector sub-system 106 keeps tracking themovements of the user. The user-feedback sub-system 110 dynamicallycontrols the graphics object on the display monitor in dependence on themovements of the user within the alert range 202.

In a fourth step 508, the contactless user-interface 102 checks whetherthe user moves out of the alert range 202. If it is determined in thefourth step 508 that the user has moved out of the alert range 202, theprocess 500 proceeds to a fifth step 510.

In the fifth step 510, the contactless user-interface 102 terminates thetracking of the user and the displaying of the graphics object on thedisplay monitor. After the fifth step 510, the process 500 returns tothe second step 504.

The alert range 202 is a spatial environment of the detector sub-system106, wherein the presence and gestures of the user affects the operationof the contactless user-interface 102. In the alert mode, anacknowledgement is given to the user via the user-feedback sub-system110. In the control mode, the relevant functionality is controlled inresponse to pre-determined control gestures, and the user-feedbacksub-system provides feedback to the user on the gestures captured. Thealert range 202 may start right at the physical boundaries of thedetector sub-system 106 and extends away from the detector sub-system106. A physical boundary of the detector sub-system 106 includes, e.g.,the physical surface of a hardware component such as a motion sensor ora position sensor accommodated at the detector sub-system 106.Alternatively, a dead-zone may be implemented intentionally between thealert zone 202 and the physical boundaries of the detector sub-system106, in case the system 100 includes the additional user-interface 112.If the detector sub-system 106 detects the presence of the user, or of abody part of the user (e.g., the user's hand), in the dead-zone, thispresence is interpreted as that the user intends to interact with theadditional user-interface 112. The contactless user-interface 102 willthen interpret the presence of the user, or of a body part of the user,within the dead-zone as that the user has left the alert range 202. Theprocess 500 will then terminate the tracking of the user and thedisplaying of the graphics object on the display monitor according tothe fifth step 510.

If it is determined in the fourth step 508 that the user has not movedout of the alert range 202, the process 500 proceeds to a sixth step512.

In the sixth step 512, it is determined whether the user has carried outthe pre-determined initialization gesture. If it is determined in thesixth step 512 that the user has not carried out the pre-determinedinitialization gesture, the process 500 returns to the third step 506.If it is determined in the sixth step 512 that the user has carried outthe pre-determined initialization gesture, the process 500 continueswith a seventh step 514.

In the seventh step 514, the detector sub-system 106 determines theapplicable one of multiple control sectors in the alert range. Examplesof an alert range with multiple control sectors are given in thediagrams of FIGS. 3 and 4, discussed above. If there is only a singlecontrol sector in the alert range 202, the seventh step 514 is absentfrom the process 500. After the seventh step 514, the process continuesto an eighth step 516.

In the eighth step 516, the user-feedback sub-system 110 controls thedisplay monitor to show a control representation, i.e., a representationof the controllability of the functionality associated with theapplicable control sector. For example, if the functionality comprisesthe adjustment of the volume of a sound, or the brightness of a lamp,the control representation comprises a linear scale indicative of arange of magnitudes that the volume or the brightness can assume. Thecurrent magnitude of the volume or of the brightness is graphicallyindicated on the linear scale. The associated pre-determined controlgesture is then operative to adjust the volume or the brightness as wellas to adjust the current magnitude indicated graphically on the linearscale. As another example, the functionality comprises the selection ofa specific one of a plurality of items of information content. The itemsmay be represented in a playlist or in an electronic program guide(EPG). The control representation comprises the playlist or the EPG, ora part thereof, with a highlight indicating the item currentlyselection. The associated pre-determined control gesture is thenoperative to select a new item as well as to adjust the position of thehighlight in the control representation so as to correspond with theitem newly selected. After the eighth step 516, the process continueswith a ninth step 518.

In the ninth step 518, the contactless user-interface 102 determineswhether or not the user's movements are interpreted as a pre-determinedcontrol gesture applicable to the current control sector determined inthe seventh step 514. If it is determined in the ninth step 518 that theuser's movements cannot be interpreted as an applicable pre-determinedcontrol gesture, the process 500 proceeds with a tenth step 520.

In the tenth step 520, it is determined whether or not the user hasmoved out of the alert range 202. If it is determined in the tenth step520 that the user has moved out of the alert range 202, the process 500returns to the fifth step 510. If it is determined in the tenth step 520that the user has not left the alert range 202, the process 500 returnsto the seventh step 514.

If it is determined in the ninth step 518 that the user's movements areinterpreted as an applicable pre-determined control gesture, the process500 proceeds with an eleventh step 522.

In the eleventh step 522, the functionality is controlled in accordancewith the temporal and spatial characteristics of the user's movements.The actual movement as captured by the detector sub-system 106 is mappedonto an applicable pre-determined control gesture. As mentioned earlier,a gesture is a deliberate movement of a position of, e.g., the user'shand. The actual movement of the user's hand is characterized bychanging a position of the hand relative to some reference position,changing an orientation of the hand relative to a reference orientation,and changing a shape of the hand relative to a reference shape. Inpractice, an actual movement cannot be repeated with an accuracy of, saya few millimeters in each of the dimensions characterizing the movement.The actual gesture as captured by the detector sub-system 106 istherefore to be compared to one or more pre-determined control gesturesapplicable to the applicable control sector. If a comparison with aspecific applicable, pre-determined control gesture reveals adiscrepancy of a magnitude within a pre-determined margin, the actualgesture is treated as equivalent to the specific, applicablepre-determined control gesture.

Remember that in the eighth step 516, the user-feedback sub-system 110generated a control representation on the display monitor in the form ofa graphics object. In the eleventh step 522, the user-feedbacksub-system 110 controls the displayed control representation also inaccordance with the temporal and spatial characteristics of the user'smovements, thus providing a visual feedback to the user of the effect ofthe user's gestures on the functionality being currently controlled.

The control of the functionality and the control of the displayedcontrol representation continue until it is determined in a twelfth step524 that the adjustment or control of the functionality can beterminated. Termination is affirmed if, for example, the user retreatsfrom the applicable control sector or if the user retrieves his/her handfrom the applicable control sector. Alternatively, the user mayterminate the current control by means of a pre-determined halt-gesturethat is interpreted by the contactless user-interface 102 as that thecontrol is to be halted. If it is determined in the twelfth step 524that the user has stopped the control, the process returns to the tenthstep 520.

FIGS. 6, 7, 8 and 9 illustrate an example of a graphics representationof the acknowledgement from the user-feedback sub-system 110 in thealert mode of the contactless user-interface 102. The user-feedbacksub-system 110 comprises a display monitor 602. Consider the operationaluse of the system 100, i.e., an operational state of the system, whereinthe power is on and wherein the user is beyond the alert range 202. Inthis operational state, the display monitor 602 is controlled to displaycontent information to the user, i.e., information that is semanticallymeaningful to the user if he/she watches the display monitor 602. In theexample of FIGS. 6-9, the content information is in the form of agraphics object 604 representing an analog clock. The hands of the clockin the graphics object 604 are controlled to indicate the current timeof the day.

In FIG. 6, the user is represented by a hand 606. The hand 606 isoutside the alert range 202 of the detector sub-system 106. The displaymonitor 602 is displaying the analog clock 604.

In FIG. 7, the hand 606 is entering the alert range 202. The detectorsub-system 106 detects the hand 606 and the contactless user-interface102 enters the alert mode. In the alert mode, the user-feedbacksub-system 110 controls the display monitor 602 to morph the graphicsobject of the analog clock 604 into a collection of particles 702 upondetection of the hand 606.

In considering the collection of particles 702: as known in the field ofcomputer-generated graphics, particle animation is typically applied tocreate a rather complex graphics structure from relatively simple,abstract descriptions. The rather complex graphics structure can be madeto change dynamically in a perceptibly convincing manner using modestcompute power. For more background see, e.g., “Particle Animation andrendering Using Data Parallel Computing”, Karl Sims, Computer Graphics,Vol. 24(4), August 1990, pp. 405-413; or “Modeling Surfaces of ArbitraryTopology with Dynamic Particles”, Richard Szeliski et al., 1993 IEEEComputer Society Conference on Computer Vision and Pattern Recognition,Proceedings CVPR '93, pp. 82-87.

Particle animation is used in the examples of FIGS. 6-9 to create agraphics object that represents the user's hand 606 on the displaymonitor 602. The graphics object is here the collection of particles702. The particles are individually controlled to dynamically changetheir positions, so as to mirror the actual movements of the hand 606 ascaptured by the detection sub-system 106. As discussed above, themirroring of the user's movements by the graphics object contributes tothe user-friendliness of the system 100. Implementing this graphicsobject by means of particle animation has an advantage that the shapeand movements of any real-life object, as captured by the detectorsub-system 106 within the alert range 202, can be mimicked in aconvincing manner, be it the user's hand, the user's leg, or the beardof Santa Claus if he were to intend to control the system pogonally(i.e., by means of his beard) via the contactless user-interface 102.

In FIG. 8, the hand 604 has entered the alert range 202 and thedetection sub-system 106 is tracking the movements of the hand 606. Theuser-feedback sub-system 110 controls the display monitor 602 so as tohave the collection of particles 702 mirror the movements of the hand606.

In FIG. 9, the hand 604 has come closer to the detector sub-system 106,and the collection of particles 702 is occupying a larger part of thescreen real estate of the display monitor 602 than in FIG. 8, and ismirroring the current movements of the hand 604.

If the user removes his/her hand 606 from the alert range 202 uponreaching any of the states illustrated in the diagrams of FIGS. 7, 8 and9, the user-feedback subsystem 110 morphs the collection of particles702 back again into the analog clock 604 in the diagram of FIG. 6.

FIGS. 10 and 11 are diagrams illustrating the operation of theuser-feedback sub-system 110 when the contactless user-interface 102 isin the control mode. The user-feedback sub-system 110 is operative toprovide control feedback to the user.

It is assumed that the user's hand 606 has entered a control sectorwherein a first functionality of the system 100 is controlled by a firstpre-determined control gesture and wherein a second functionality of thesystem 100 is controlled by a second pre-determined control gesture. Thecontactless user-interface 102 interprets an actual movement of the hand606 as being the first pre-determined control gesture, if the actualmovement has a main vector component substantially along the Y-axis ofthe Cartesian coordinate system 402 of FIG. 4. The contactlessuser-interface 102 interprets an actual movement of the hand 606 asbeing the second pre-determined control gesture, if the actual movementhas a main vector component along the Z-axis of the Cartesian coordinatesystem 402 of FIG. 4.

As illustrated in the diagram of FIG. 10, the control representation ofthe first functionality is a first graphics object 1002 that comprises ahorizontal array of a plurality of boxes. Each respective one of theboxes represents a respective magnitude, level or state to which thefirst functionality can set in the control mode of the contactlessuser-interface 102. Assume that the hand 606 has entered the relevantcontrol sector at a time t=T1. Up to the time t=T1 the firstfunctionality has had the state that corresponds to the third box of thearray. The third box of the horizontal array is highlighted. Whilehis/her hand 606 is in the relevant control sector, the user starts tomove his/her hand 606 in the direction of the positive Y-axis. Thedetector sub-system 106 tracks the movement. The detector output causes,via the control sub-system 104, the state of the first functionality tochange in accordance with the movement of the hand 606 in the positivedirection along the Y-axis. The detector output also causes theuser-feedback sub-system 110 to change the first graphics object 1002 inaccordance with the movement of the hand 606 being tracked. At a timet=T1+ΔT, the highlight has left the third box and the fourth box of thehorizontal array is highlighted. At a time t=T1+3ΔT, the highlight hasleft the fourth box and the seventh box of the horizontal array ishighlighted. Apparently, the user has realized that he/she has overshotthe intended final state, and the user moves his/her hand 606 back inthe negative direction along the Y-axis. At a time t=T1+7 ΔT, thehighlight has left the seventh box and the sixth box of the horizontalarray is highlighted.

As illustrated in the diagram of FIG. 11, the control representation ofthe second functionality is a second graphics object 1102 that comprisesa vertical slider 1104. Each respective vertical position of the slider1104 corresponds to a respective level to which the second functionalitycan be set in the control mode of the contactless user-interface 102.Assume that the hand 606 has entered the relevant control sector at atime t=T1. Up to the time t=T1 the second functionality has had thelevel that corresponds with the position of the slider 1104 as indicatedat t=T1. While his/her hand 606 is in the relevant control sector, theuser starts to move his/her hand 606 in the direction of the positiveZ-axis. The detector sub-system 106 tracks the movement. The detectoroutput causes, via the control sub-system 104, the state of the secondfunctionality to change in accordance with the movement of the hand 606in the positive direction along the Z-axis. The detector output alsocauses the user-feedback sub-system 110 to change the second graphicsobject 1102 in accordance with the movement of the hand 606 beingtracked. At a time t=T1+ΔT, the slider 1104 has moved to a highervertical level. The higher level at the time t=T1+ΔT corresponds withthe vertical position that the hand 606 assumes at the time t=T1+ΔT. Ata time t=T1+5ΔT, the slider 1104 has moved to a yet higher verticallevel. The yet higher level at the time t=T1+5ΔT corresponds with thevertical position that the hand 606 assumes at the time t=T1+5ΔT.

The transition from the alert mode of the contactless user-interface 102to the control mode goes together with the transitioning of displayingthe acknowledgment (in above example: the collection of particles 702)that mirrors the user's movements, to displaying the control feedback(in above example: the first graphics object 1002 or the second graphicsobject 1102) that mirrors the user's gestures. The transitioning betweendisplaying the acknowledgment and displaying the control feedback, andvice versa, can be implemented again using a cross-fading technique or amorphing technique.

Note that the first graphics object 1002 and the second graphics object1102 can be displayed on the display monitor 602 at the same time. Thecontactless user-interface 102 discriminates between actual gestures ofthe user, in this example based on their main vector component, so thateither the first functionality or the second functionality is controlledif both their graphics representations (i.e., the first graphics object1002 and the second graphics object 1102) are being displayed at thesame time. This prevents an actual gesture, meant by the user to controlthe state of the first functionality, from affecting the state of thesecond functionality and vice versa.

1. A system with a contactless user-interface configured for a user'scontrolling a functionality of the system through contactlessinteraction with the contactless user-interface, wherein: thecontactless user-interface has a detector sub-system and a user-feedbacksub-system; the contactless user-interface is configured for operatingin one of: an alert mode and a control mode; in the alert mode, thecontactless user-interface is configured for controlling theuser-feedback sub-system to provide an acknowledgement to the user, inresponse to the detector sub-system having detected a presence of theuser within a pre-determined alert range; the contactless user-interfaceis configured for transitioning from the alert mode to the control modein response to the detector sub-system detecting a pre-determinedinitialization gesture made by the user within the pre-determined alertrange; and in the control mode, the contactless user-interface isconfigured for controlling the functionality in response to the detectorsubsystem detecting a pre-determined control gesture of the user carriedout within the pre-determined alert range, wherein the system has anadditional user-interface; and the additional user-interface isconfigured for user control of an additional functionality of the systemthrough physical contact with the additional user-interface; thedetector sub-system is operative to inactivate user control of thefunctionality via the contactless user-interface upon detecting the userapproaching the additional user-interface in a pre-determined manner. 2.The system of claim 1, wherein the user-feedback sub-system isconfigured to provide to the user control feedback on a change in astatus of the functionality in response to the pre-determined controlgesture, or wherein the user-feedback sub-system is configured fordynamically adjusting the acknowledgement under control of the detectorsub-system tracking the user within the alert range, or wherein theuser-feedback sub-system is configured for dynamically adjusting thecontrol feedback under control of the detector sub-system tracking theuser within the alert range. 3-5. (canceled)
 6. Control software on acomputer-readable medium configured for use on a system with acontactless user-interface, wherein: the contactless user-interface isconfigured for a user's controlling a functionality of the systemthrough contactless interaction with the contactless user-interface; thecontactless user-interface has a detector sub-system and a user feedbacksub-system; the control software has first instructions for implementingoperation of the contactless user-interface in an alert mode; thecontrol software has second instructions for implementing operation ofthe contactless user-interface in a control mode; the first instructionscomprise third instructions for controlling the user-feedback sub-systemto provide an acknowledgement to the user, in response to the detectorsub-system having detected a presence of the user within apre-determined alert range; the first instructions comprise fourthinstructions for causing the contactless user-interface to transitionfrom the alert mode to the control mode in response to the detectorsub-system detecting a pre-determined initialization gesture made by theuser within the pre-determined alert range; and the second instructionscomprise fifth instructions for controlling the functionality inresponse to the detector subsystem detecting a pre-determined controlgesture of the user carried out within the pre-determined alert range,wherein: the system has an additional user-interface; the additionaluser-interface is configured for the user's controlling an additionalfunctionality of the system through physical contact with the additionaluser-interface; the second instructions comprise tenth instructions forinactivating the user controlling the functionality via the contactlessuser-interface upon the detector sub-system detecting the userapproaching the additional user-interface in a pre-determined manner. 7.The control software of claim 6, wherein the second instructionscomprise sixth instructions for controlling the user-feedback sub-systemto provide to the user control feedback on a change in a status of thefunctionality in response to the pre-determined control gesture, orwherein the first instructions comprise seventh instructions for controlof the user-feedback sub-system for dynamically adjusting theacknowledgement under control of the detector sub-system tracking theuser within the alert range, or wherein the second instructions compriseninth instructions for controlling the user-feedback sub-system todynamically adjust the control feedback under control of the detectorsub-system tracking the user within the alert range. 8-10. (canceled)11. A method of enabling a user to control a functionality of a systemthrough contactless interaction with the system, wherein: the method hasan alert mode process and a control mode process the method comprises:in the alert mode process, providing an acknowledgement to the user, inresponse to detecting a presence of the user within a pre-determinedalert range; transitioning from the alert mode process to the controlmode process in response to detecting a pre-determined initializationgesture made by the user within the pre-determined alert range; and inthe control mode process, controlling the functionality in response todetecting a pre-determined control gesture of the user carried outwithin the pre-determined alert range, wherein: the system has anadditional user-interface; the additional user-interface is configuredfor the user's controlling an additional functionality of the systemthrough physical contact with the additional user-interface; the methodcomprises inactivating the controlling of the functionality through thecontactless interaction upon detecting the user approaching theadditional user-interface in a pre-determined manner.
 12. The method ofclaim 11, wherein the control mode process comprises providing to theuser control feedback on a change in a status of the functionality inresponse to the pre-determined control gesture, or wherein the alertmode process comprises dynamically adjusting the acknowledgement undercontrol of tracking the user within the alert range, or wherein thecontrol mode process comprises dynamically adjusting the controlfeedback under control of tracking the user within the alert range.13-15. (canceled)
 16. A user-interface for use in a system, wherein theuser-interface comprises a contactless user-interface configured for auser's controlling a functionality of the system through contactlessinteraction with the contactless user-interface, wherein: thecontactless user-interface has a detector sub-system and a user-feedbacksub-system; the contactless user-interface is configured for operatingin one of: an alert mode and a control mode; in the alert mode, thecontactless user-interface is configured for controlling theuser-feedback sub-system to provide an acknowledgement to the user, inresponse to the detector sub-system having detected a presence of theuser within a pre-determined alert range; the contactless user-interfaceis configured for transitioning from the alert mode to the control modein response to the detector sub-system detecting a pre-determinedinitialization gesture made by the user within the pre-determined alertrange; and in the control mode, the contactless user-interface isconfigured for controlling the functionality in response to the detectorsubsystem detecting a pre-determined control gesture of the user carriedout within the pre-determined alert range, wherein: the user-interfacehas an additional user-interface; the additional user-interface isconfigured for the user's controlling an additional functionality of thesystem through physical contact with the additional user-interface; thedetector sub-system is operative to inactivate the user controlling thefunctionality via the contactless user-interface upon detecting the userapproaching the additional user-interface in a pre-determined manner.17. The user-interface of claim 16, wherein the user-feedback sub-systemis configured to provide to the user control feedback on a change in astatus of the functionality in response to the pre-determined controlgesture, or wherein the user-feedback sub-system is configured fordynamically adjusting the acknowledgement under control of the detectorsub-system tracking the user within the alert range, or wherein theuser-feedback sub-system is configured for dynamically adjusting thecontrol feedback under control of the detector sub-system tracking theuser within the alert range. 18-20. (canceled)
 21. System according toclaim 1, wherein the system detector sub-system is configured to detecta main vector component of a vector representing a gesture of the useras a directed path within the pre-determined alert range, wherein if thedirected path lies in the direction from the user towards the additionaluser-interface, and if a rate of change of this main vector componentexceeds a pre-determined threshold magnitude, the detector sub-system isconfigured to interpret the movement or gesture as that the user isreaching for the additional user-interface.
 22. System according toclaim 1, wherein the system has one or more functionalities that can becontrolled by the user via the contactless user-interface, and whereinthe directed path of any respective one of the pre-determined controlgestures for the one or more functionalities does not have a vectorcomponent in the direction from the user towards the additionaluser-interface.
 23. System according to claim 1, wherein the contactlessuser-interface is configured for resetting the functionality to thestate the functionality had before starting to control thefunctionality, upon the user actually touching, or actually interactingwith, the additional user-interface.
 24. System according to claim 21,wherein the system is configured such that if the directed path of aparticular one of the pre-determined control gestures has a main vectorcomponent along said direction, the contactless user-interface isconfigured in such a way that the functionality, associated with thisparticular pre-determined control gesture, is not a criticalfunctionality.
 25. The system of claim 1, wherein the additionaluser-interface comprises one or more buttons, and/or one or more dials,and/or one or more sliders, and/or one or more levers, and/or a touchscreens.
 26. System according to claim 1, wherein the firstfunctionality of the system is user-controllable via the contactlessuser-interface, and the additional functionality of the system isuser-controllable via the additional user-interface, the firstfunctionality being different from the additional functionality, or thefirst functionality being the same as the additional functionality. 27.The system of claim 1, wherein the user-feedback sub-system isconfigured to respond differently to a same pre-determined controlgesture, according to whether the control gesture carried out indifferent control sectors within the alert range.